Crane drive apparatus, system and method of operating same



Feb. 11, 1964 J. G. GRALL ETAL CRANE DRIVE APPARATUS, SYSTEM AND METHOD OF OPERATING SAME Original Filed July 28, 1958 2 Sheets-Sheet 1 INVENTORS JOHN G @RHLL EDWARD B. NICKLES ATTOKNEV 1964 J. G. GRALL ETAL CRANE DRIVE APPARATUS, SYSTEM AND METHOD OF OPERATING SAME Original Filed July 28, 1958 2 Sheets-Sheet 2 L A Y Y mmmsww H R W Z WFJ NB E N H W? 06 5 A 1 United States Patent 3,120,896 CRANE DRIVE APPARATUS, SYSTEM AN METHGD 0F OZERATING SAME John G. Grail and Edward B. Nickles, Manitowoc, Roche J. Van De Hey, Whitelaw, and John D. West, Manitowoc, Wis., assignors to Manitowoc Engineering Corp, Manitowoe, Wis, a corporation of Wisconsin Original application July 28, 1958, Ser. No. 751,545, new Patent No. 3,088,564, dated May 7, 1963. Divided and this application July 18, 1962, Ser. No. 210,739 9 Claims. (Cl. 212F258) This invention relates to machinery, such as cranes which may have excavating attachments like shovels, clamshells and draglines attached thereto, and more particularly to an improved drive system or mechanism for such machines, and the method of operating same, wherein separate engines are employed to power a hoisting assembly and a swing assembly thereof.

This application is a division of cc-pending United States application Serial Number 751,545, filed July 28, 1958, for Drive System and Mechanism now United States Patent Number 3,088,564 issued on May 7, 1963.

It is customary, in crane type excavators, to provide a drive system or mechanism which includes a single engine to drive the several functions, the power being transmitted and controlled by means of friction clutch devices. In such a system or mechanism the speed of the engine is customarily regulated by a governor which tends to hold a constant speed by varying the engine torque to compensate for load changes. It is necessar therefore, for the clutch devices to slip while accelerating a load, resulting in the continual wear of the friction linings and requiring frequent adjustment and periodic replacement. This is particularly true of swing clutch devices which are usually employed to reverse the rotation of the crane by application of the appropriate clutch device to first decelerate the swing and then accelerate same in an opposite direction. During such a reversal it is necessary that the clutch device must slip until the crane reaches its governed swing speed, resulting in severe heating and wear of the friction surfaces.

A second drawback in the conventional type machine, having a single engine drive system or mechanism, lies in the inherent inability of a single engine to maintain a given speed under changing load due to governor droop. Thus, for example, an engine laboring under a hoisting load will be further slowed by the application of a swing load with the result that cycle time is considerably greater than it would be if the swing speed were not reduced by the hoisting load.

An additional drawback in the conventional type ma chine results from driving both the hoist and swing assemblies from the same power source whereby the speeds of these functions are not adjustable with respect to each other. As a result, it frequently happens that the speed of the hoist assembly is such that the load is raised to the maximum of the machine before the desired angle of swing is completed. It is then necessary to hold the load elevated with a brake until the swing is completed. Power is obviously wasted in such a cycle because the load is raised faster than necessary. The converse of this also occurs in some operations, i.e., the swing must be delayed until the hoist has lifted the load sufficiently to clear a high spoil pile. Such a delay results in cycle time wasted with a resulting loss of machine efliciency.

It is an object of the present invention to provide machinery with an improved drive system or mechanism wherein the slipping of friction clutch devices of the machinery and the consequent wear thereof is greatly reduced.

It is a further object of the invention to provide machinery, such as excavator cranes, with an improved drive system or mechanism wherein the swing speed of the crane is unaffected by the hoisting load thereof.

It is also an object of this invention to provide cranes with an improved 'drive system or mechanism wherein the swing and hoisting speeds of the crane are individually variable.

An additional object of this invention is to provide machinery with apparatus to coordinate a friction clutch control with a load being handled by the machinery.

Another object of this invention is to provide machinery such as an excavating crane with a drive system or drive mechanism wherein the swing and hoist functions of the crane are each operated by assemblies which employ pressure fluid responsive clutch devices each of which are driven by a power source having a ifluid pressure responsive control and apparatus is provided for enabling the clutch devices of the assemblies to be engaged prior to any appreciable advance in the control for the respective power source so that slippage, wear and overheating of the clutch devices are substantially eliminated.

It is still another object of this invention to provide machinery such as excavating cranes with an improved drive system or drive mechanism wherein the swing and hoist functions of the crane are operated by assemblies with apparatus that enables the operating cycle time of the crane in performing the hoist and swing functions to be decreased which results in a desired increase in the performance and production thereof.

This invention also contemplates, as an object thereof, a method of operating a machine having a fluid pressure responsive clutch device driven by a power source having a fluid pressure responsive control wherein the method comprises first engaging the clutch device through fluid pressure of a given range and then increasing the effective drive of the power source by fluid pressure which is greater than the range of fluid pressure which causes the clutch device to be engaged.

In addition, this invention further contemplates, as an object thereof, a method of operating the swing and hoist functions of an excavator crane wherein the swing and hoist functions are performed by assemblies each of which are driven by a fluid pressure actuated clutch device through an engine having a fluid pressure advanced throttle control and the method comprises the provision of apparatus for enabling fluid pressure within a given range to first cause engagement of the clutch devices and thereafter providing fluid pressures which are greater than the given range of fluid pressures for enabling the throttle control of the respective engine to be advanced.

Other objects and important features of this invention will be apparent from a study of the specification following taken with a drawing, which together show, describe, disclose and illustrate the preferred embodiment or modification of the invention and what is now considered to be the best mode of practicing the principles thereof. Still other embodiments or modifications may be suggested to those having the benefit of the teachings herein, and such other embodiments or modifications are intended to be reserved as they fall within the scope and breadth of the subjoined claims.

In the drawing:

FIGURE 1 is an isometric view of a machine shown for the purpose of illustration as being a mobile type crane which is provided with the improved drive system and drive mechanism of this invention;

FIGURE 2 is a top plan view, partly in section, of a part of the machine illustrated in FIGURE 1 showing the upper works of the crane as having the drive system or mechanism according to this invention employed therein, and

FIGURE 3 is a side elevational sectional view taken along the line IIIIII of FIGURE 2.

Attention is now directed to FIGURE 1 of the drawing wherein a machine 2, such as a crane, is shown for the purpose of illustration, with the crane 2 being mounted ona mobile type velncle chassis 4 and having pivotally or hingeably mounted boom structure 6 projecting threfrom to which there may be attached shovels, clamshells, draglines, or the like with the boom structure 6 being suitably controllably supported by cable arrangements 8 from the upper works of the crane 2.

Referring now to FIGURES 2 and 3 of the drawing, the machine 2 is provided with a rotating bed It? mounted on rollers (not shown) which ride on an upper surface of a roller path 12 defined by a ring gear to permit swinging of the machine 2 about a vertical axis. A kingpin 14 is centrally fixed in the ring gear and serves to keep internal gear teeth 18 in the roller path 12 to power the swinging movement of the machine 2.

The rotating bed comprises a pair of trifurcated boom hinge members 20 at the forward portion thereof, side frames 22 extending along each side serve to stiffen the bed 10 and also to support the several shafts which comprise the operating machinery, and engine supports 24 located adjacent to the rear of the bed It A hoist system is provided for the machine 2 and the hoist system comprises a pair of drum shaft 26-26 journaled in pillow blocks mounted on the side frames 22 and are driven through suitable gears from a countershaft 28 which is similarly mounted on the side frames 22 and which, in turn, is driven from a pinion 30 which is integral with a sprocket 32.

A drive system or mechanism is provided for driving the drum shafts 2626 of the hoist system as well as a swing system of the machine, to be described hereinafter, and the drive system or mechanism comprises a power source having a first engine 36, which may be called the hoist engine, and the sprocket 32 of the hoist system is driven by means of a chain 34 by the first engine 36 of the power source.

The power source of the drive system or mechanism further comprises a second engine 58, which may be called the swing engine, and the swing system comprises the aforementioned swing pinion 16 which is mounted on a swing pinion shaft 38 and is driven through suitable gearing from a vertical swing shaft 40. Mounted at the top of the shaft 49 is a swing bevel gear 42 which engages, and may be driven by either of, a pair of bevel gears 44, 46 which are rotatably mounted on a horizontal swing drive shaft 48 and driven by a pair of fluid pressure actuated swing clutch devices St), 52 respectively, which are also mounted on the drive shaft 48 and are driven by it. The drive shaft 43 extends outwardly of the sprocket 32 and carries a sprocket 54 which is driven by a chain 56 from the second engine 58.

As shown in FIGURES 2 and 3 of the drawing, the sprocket 32 and the pinion 3i? are carried on anti-friction bearings, tapered roller bearings being shown, mounted on the horizontal swing drive shaft 48 whereby the sprocket 32 cannot drive the drive shaft 48 but is merely positioned thereby. This arrangement is not a necessary part of the invention but is merely a convenient expedient for the conversion of a conventional type machine to take advantage of the present invention. In this respect it is to be noted that in a conventional type machine the pinion 30 is normally driven by the drive shaft 48 which, in turn, is driven by a single sprocket and thus all of the maclnnery is driven from the drive shaft 48.

Each of the engines 36 and 58 of the drive system or mechanism may be preferably provided with a hydraulic torque converter 60. While it is not essential that hydraulic torque converters be used, it is desirable that some power transmisison device he used which will permit the driven machinery to be fully stalled, at least at low engine torque, without stalling the respective en-' gine. Such devices include so-called fluid clutch devices and eddy current clutch devices.

Each of the engines 36 and 58 of the drive system or mechanism is further provided with a fluid pressure actuated control, which, as illustrated, is in the form of a conventional governor 62, comprising a throttle lever 64 or other suitable means whereby the speed of the respective engine may be varied.

Fluid pressure actuated drum clutch devices are provided which comprise a ciutch spider es carried by each drum shaft 25 and rotatably driven thereby. Each clutch spider 65 drives a clutch shoe 63 carried thereby in a conventional manner whereby the respective clutch shoe 68. may be caused to engage a clutch drum 70 carried by a cable drum 72 rotatabiy mounted on each drum shaft 26. It will thus be seen that when the clutch shoe 6% is caused to engage the clutch drum 70, the cable drum 72 will turn with the shaft 26.

For the sake of brevity, the operation of only one of the drum clutch devices will be descnibed and it is to be noted that the clutch shoe 68 is connected by suitable linkage to a fluid pressure motor (shown schematically) carried by the clutch spider 66, which may comprise a cylinder 74 having a piston 76 therein. A spring 78 is provided to retract the clutch shoe 68 when fluid pressure is not being applied to the piston 76 to engage the clutch device.

Fluid pressure to operate the clutch device is supplied through an axial passage 89 in the drum shaft 26, a rotary joint 82, and a line 34, from modulating control valving 86 at the operators station, which in turn is supplied from a pressure fluid source 87 through suitable conduit means 89.

A second fluid pressure motor 88 is provided to operate the engine governor 62 of the hoist engine 36. This governor is arranged to advance the speed of the engine 36 upon application of fluid pressure and a retract spring 90 is provided to slow the speed of the engine 36 when fluid pressure is reduced. The throttle fluid pressure motor 83 is supplied with fluid pressure from the operators control valving 86 through a throttle control line 92.

While only the front cable drum 72 is shown and de scribed in detail, it should be understood that the rear cable drum 72 is similar in construction and operation and is controlled by similar but separate modulating control valving 94.

Because both cable drums 7272 are driven from the same engine 36, it is necessary that the throttle pressure motor 88 be operable from either of the modulating control valving 86, 94. It is, therefore, necessary to provide structure to prevent feedback from the throttle control line 92, when it is charged from one modulating valving, from entering the other clutch device pressure line and thus engaging both drum clutch devices.

A shuttle valve 96 serves as convenient structural expedient for such feedback prevention. The shuttle valve 96 comprises a cylinder having an inlet passage terminating in a valve seat 98 at each end and an outlet passage 100 at its center. A shuttle 102 comprising a valve spool is freely movable in the cylinder and can seal against either of the valve seats 98. It should be apparent that when the modulating control valving 94 is opened to engage the rear drum clutch device, pressure fluid will enter the shuttle valve 96 and hold the shuttle 192 against the opposite inlet port thus preventing the passage of fluid to the front drum clutch device but permitting fluid to flow to the fluid pressure throttle motor 88. When the modulating control valving 94 is closed and the control valve 86 is opened to engage the front drum clutch device, pressure fluid will force the shuttle 192 against the inlet seat and prevent pressure fluid from entering the line for the rear drum clutch device. The shuttle 102 will, of course, move beyond the outlet and thus permit fluid to enter the line 92 to actuate the throttle fluid pressure motor 88. Thus either modulating control valving 86, 94 may be used to actuate the respective drum clutch device and the throttle of the hoist engine 36 without affecting the other drum clutch device. In the event that the modulating control valving are both opened at the same time, the one which is opened to the greater pressure setting will deter mine the position of the shuttle 102 and thus the speed of the hoist engine 36.

An essential feature of the present invention lies in the provision of apparatus for enabling the clutch fluid pressure motors 74, 76, 78 to be responsive to a lower range of control pressures than the throttle fluid pressure motor 88. This may be accomplished through the proper selection of springs and cylinder sizes and/ or through the use of suitable linkage (not shown). Because the clutch device responds to pressures which are less than those required to actuate the throttle of the hoist engine 36, the clutch device will be engaged by increasing control pressure before the engine torque starts to increase. Since at this point the hoist engine 36 is only idling, and the torque output from the torque converter is very low, application of the drum clutch device is accomplished with a minimum of clutch wear due to the absence of high speed, high torque slippage.

As fluid pressure in the control system is further increased by the operator by means of the modulating control valving, the throttle fluid pressure motor 83 will open the governor 62 of the hoist engine 36 causing the engine torque, and consequently the torque ultimately available at the drum, to increase. However, that same pressure is available at the drum clutch device to increase the pressure of the shoe 68 on the drum 70 to permit it to transmit more torque. Thus the drum clutch device is always capable of transmitting the torque which is transmitted to it. While clutch slippage is kept to a minimum by the present system, it should be noted that at light loads the clutch devices may be engaged very gently with the consequent slippage when it is desired to accelerate a load extremely slowly. However, since this slippage occurs only at light loads and slow relative speeds, the clutch life is not appreciably affected.

Construction and operation of the swing clutch devices 50, 52 is similar to that of the drum clutch devices. A pair of modulating control valving 104, 166 is connected to a pair of passages in the swing shaft 48 and thence to fluid motors incorporated in the swing clutch devices 50 and 52. A shuttle valve 110 is connected between the two clutch control lines and has its outlet connected to another throttle fluid pressure motor 112 on the swing engine 58.

The clutch devices 50, 52 and the throttles 62, 64 response pressures in the swing assembly are balanced by suitable apparatus in the same manner as those of the hoist assembly so that the clutch devices 50, 52 will be applied before the engine torque is increased and the clutch devices engaged with a minimum of slippage The modulating control valving 104 and 106 for the swing clutch devices 50, 52 may be conveniently arranged to be controlled by 'a single actuator (not shown) which will operate either of the modulating valving depending upon the direction of motion from a neutral position, thereby permitting swing control in either direction with a single lever.

All of the clutch device control valving are supplied with pressure fluid from an engine driven source, such as the pressure fluid source 87 through the conduit means 89, which may supply a distribution manifold (not shown) to which the valving may be connected.

In actual practice, it has been found that a Midland valve, No. XN'3440, manufactured by Midland-Ross Corporation of Owosso, Michigan, or a Flexair type valve manufactured by Westinghouse Air Brake Company of Wilmerding, Pennsylvania, will work satisfactorily as the modulating control valving 86, 94, 104- and 106 and while this valving has been illustrated in schematic manner in the drawing, it is to be understood that such valving may be of the type identified above or some other like or similar type of valving.

From the foregoing, it is believed that there has been described, disclosed, illustrated and shown a machine such as a crane having swing and hoist assemblies each driven through clutch devices by a power source wherein there is provided an improved drive system and drive apparatus together with a method of operating the machine in which the slippage and consequent wear and overheating of the clutch device is minimized; in which the speed of the swing function and the speed of the hoist function are entirely independent and separate; in which the swing and hoist functions are individually and separately controlled without necessitating the inclusion of additional controls; in which the capacities of the friction clutch devices are coordinated with the requirements of the load, and in which the cycle time for the swing and hoist function may be substantially descreased so as to increase the operational production of the machine.

While the invention has been described, disclosed illustrated and shown in terms of the preferred embodiment, arrangement or modification thereof, the scope of this invention should not be deemed to be limited by the precise embodiment, modification and arrangement as herein shown, described, disclosed and illustrated, such other embodiment, modifications and arrangements being intendded to be reserved especially as they fall within the scope of the claims here appended.

We claim as our invention:

1. In combination with a crane having hoist and swing assemblies,

drive mechanism for the assemblies, said drive mechanism comprising,

a plurality of engines,

a swing gear train driven by one of said engines through a pair of opposed fluid pressure engaged swing clutch devices,

at least two cable drums driven by the other of said engines through fluid pressure engaged drum clutch devices,

each of said engines having a fluid pressure advanced throttle,

modulating valving for connecting pressure fluid to each of said swing clutch devices,

a shuttle valve for connecting either of said swing clutch devices with the throttle of the first one of said engines awhile barring connection of said throttle with the other of said swing clutch devices,

modulating valving for connecting pressure fluid to each of said drum clutch devices,

a second shuttle valve connecting either of said drum clutch devices with the throttle of the other of said engines while barring connection of said throttle with the other of said drum clutch devices, and

apparatus for enabling each of said clutch devices to be responsive to a lower range of fluid pressure than the respective engine throttle.

2. A crane comprising, in combination, a hoist assembly and a swing assembly,

each of said assemblies having a clutch device,

drive mechanism for the assemblies, said drive mechanism comp-rising a first engine for driving the hoist clutch device,

a second engine for driving the swing clutch device,

a throttle for each of said engines,

a fluid pressure motor connected to each of the throttles,

a fluid pressure motor connected to each of said clutch devices,

modulating valving for connecting a source of pressure fluid to each of the throttle motors and to its respective clutch motor, and

apparatus for enabling each of the clutch motors to be responsive to a given range of fluid pressure and for enabling each of the throttle motors to be responsive to a range of fluid pressure which is greater than the i given range of fluid pressure for the respective clutch motor, said apparatus comprising a bias acting on each of said throttles in a throttle closing direction and a bias acting on each of said clutch devices in a clutch releasing direction with each of the throttle biases exerting a force greater than the force exerted by the bias of the respective clutch device.

3. In combination with a crane having hoist and swing assemblies,

drive mechanism for the assemblies, said drive mechanism comprising,

a plurality of engines,

a swing gear train driven by one of said engines through a fluid pressure engaged swing clutch device,

a hoist drum driven by one of said engines through a fluid pressure engaged hoist clutch device,

each of said engines having a fluid pressure advanced control,

modulating valving for communicating a source of pressure fluid to said swing clutch device and to the control of the respective engine,

modulating valving for communicating a source of pressure fluid to said hoist clutch device and to the control of the respective engine, and

apparatus for enabling each of said clutch devices to be responsive to a lower range of fluid pressure than the respective engine control.

4. A crane comprising, in combination, a hoist assembiy and a swing assembly,

drive mechanism for the assemblies, said drive mechanism comprising,

at least a pair of engines,

a fluid pressure control for each of said engines,

said hoist assembly having a fl uid pressure actuated clutch device driven by one of said engines,

said swing assembly having a fluid pressure actuated clutch device driven by another one of said engines,

modulating valving for connecting pressure fluid to each of said clutch devices and to the respective engine control, and

apparatus for enabling said clutch devices to be responsive to lower ranges of fluid pressures than the respective engine control.

5. In combination with a crane having a hoist assembly and a swing assembly,

drive mechanism for the assemblies, said drive mechanism comprising,

a fluid pressure responsive clutch device' for each of the assemblies,

a power source for each of the clutch devices,

a fluid pressure responsive control for each of the power sources,

modulating valving for connecting pressure fluid to each of said clutch devices and to the respective control, and

apparatus for enabling said clutch devices to be responsive to lower ranges of fluid pressures than the respective control.

6. In combination with a crane having hoist and swing assemblies,

a drive system for the assemblies, said drive system comprising,

a plurality of engines,

a swing gear train driven by one of said engines through a pair of opposed fluid pressure engaged swing clutch devices,

at least two cable drums driven by the other of said engines through fluid pressure engaged drum clutch devices,

each of said engines having a fluid pressure advanced control,

modulating valving for connecting pressure fluid to each of said swing clutch devices,

a shuttle valve for connecting either of said swing clutch devices with the control of the first one of said engines while barring connection of said control with the other of said swing clutch devices,

modulating valving for connecting pressure fluid to each of said drum clutch devices,

a second shuttle valve connecting either of said drum clutch devices with the control of the other of said engines while barring connection of said control with the other of said drum clutch devices, and

apparatus for enabling each of said clutch devices to "be responsive to a lower range of fluid pressure than the respective engine control.

7. In combination with a crane having hoist and swing assemblies,

a drive system for the assemblies, said drive system comprising,

a pluraiity of engines,

a swing gear train driven by one of said engines through a fluid pressure responsive swing clutch device,

a hoist drum driven by one of said engines through a fluid pressure responsive hoist clutch device, each of said engines having a fluid pressure responsive control,

modulating valving for communicating a source of pressure fluid to said swing clutch device and to the control of the respective engine,

modulating valving for communicating a source of pressure fluid to said hoist clutch device and to the control of the respective engine, and

apparatus for enabling each of said clutch devices to be responsive to a lower range of fluid pressure than the respective engine control.

8. A crane comprising, in combination, a hoist assembly and a swing assembly,

a drive system for the assemblies, said drive system comprising,

at least a pair of engines,

a fluid pressure advanced throttle control for each of said engines,

said hoist assembly having a fluid pressure actuated cable drurn clutch device driven by one of said engines,

said swing assembly having a fluid pressure actuated swing clutch device driven by another one of said engines,

modulating valving for connecting pressure fluid to each of said clutch devices and to the respective engine throttle control, and

apparatus for enabling said clutch devices to be responsive to lower ranges of fluid pressures than the respective engine throttle control.

9. In combination with a crane having a hoist assembly and a swing assembly, a drive system for the assemb lies, said drive system comprising References Cited in the file of this patent UNITED STATES PATENTS London Nov. 30, 1909 Richardson Sept. 13, 1960 

1. IN COMBINATION WITH A CRANE HAVING HOIST AND SWING ASSEMBLIES, DRIVE MECHANISM FOR THE ASSEMBLIES, SAID DRIVE MECHANISM COMPRISING, A PLURALITY OF ENGINES, A SWING GEAR TRAIN DRIVEN BY ONE OF SAID ENGINES THROUGH A PAIR OF OPPOSED FLUID PRESSURE ENGAGED SWING CLUTCH DEVICES, AT LEAST TWO CABLE DRUMS DRIVEN BY THE OTHER OF SAID ENGINES THROUGH FLUID PRESSURE ENGAGED DRUM CLUTCH DEVICES, EACH OF SAID ENGINES HAVING A FLUID PRESSURE ADVANCED THROTTLE, MODULATING VALVING FOR CONNECTING PRESSURE FLUID TO EACH OF SAID SWING CLUTCH DEVICES, A SHUTTLE VALVE FOR CONNECTING EITHER OF SAID SWING CLUTCH DEVICES WITH THE THROTTLE OF THE FIRST ONE OF SAID ENGINES WHILE BARRING CONNECTION OF SAID THROTTLE WITH THE OTHER OF SAID SWING CLUTCH DEVICES, MODULATING VALVING FOR CONNECTING PRESSURE FLUID TO EACH OF SAID DRUM CLUTCH DEVICES, 